Need help to ID track maintenance

I saw these two cars on the tracks near my house today. I think they are maintenance cars because they were moving real slow and one had some device that would drop down from under the car and clamp on something for a couple of seconds. Then move a few feet and do it again.
I would love to know exactly what they were doing. Thanks.

http://www.railroadforums.com/forum/ind ... 79&slide=0

http://www.railroadforums.com/forum/ind ... 78&slide=0

tamper. they shake and squeeze ballast next to and under the ties.

They are not tampers.
The first is a Nordco Spike Puller-
https://www.nordco.com/products-catalog ... --SP2R.htm

The second is a Sperling OTM (old track material) scrap pickup machine-
http://www.sperlingrailway.com/RailwayP ... -Machine-2